Information processing system and control method therefor

ABSTRACT

A client specifies a first authorization server based on an authorization response corresponding to an authorization request transmitted by the client, and transmits a token request for requesting an authorization token to the first authorization server. The first authorization server issues the authorization token in response to the token request.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to an information processing system forspecifying an authorization end point of an authorization server, and acontrol method therefor.

Description of the Related Art

There is a configuration in which an application included in a clientsuch as a multifunction peripheral (MFP) acquires an authorization tokenfrom an authorization server via a token provider included in theclient. The authorization token is a token indicating that a client,which has received delegation of authority by an authorization operationperformed by an authenticated user, has permitted access to anapplication programming interface (API) released by a resource server.By using the authorization token, the client can access the API releasedby the resource server without having to pass user information such asan ID, password information, and authorization information to theresource server or the authorization server. For example, if the clientis an MFP, by using the acquired authorization token, the MFP can useweb services such as a print service and a business form service thatare provided by the resource server to display data and executeprinting.

The authorization token is issued by the authorization server executingan Authorization Code Grant flow in a standard protocol called OAuth2.0. More specifically, the user authorizes, through a web browser, theclient to use the web services provided by the resource server, and theauthorization server issues the authorization token to the tokenprovider that has transmitted a token request. The token request is arequest transmitted to the authorization server so that the tokenprovider can acquire the authorization token.

Japanese Patent Application Laid-Open No. 2017-107396 discusses a systemin which an application included in a client acquires an authorizationtoken from an authorization server via a token provider included in theclient.

SUMMARY OF THE INVENTION

According to an aspect of the present invention, an informationprocessing system includes a client configured to transmit anauthorization request used by a user to authorize access by the clientto a resource server, and two or more authorization servers present indifferent regions. The authorization servers each include a firstspecifying unit configured to specify a first authorization server inwhich user information about the user who authorizes the access islocated. The client includes a second specifying unit configured tospecify the authorization servers present in the regions based on regioninformation about the regions. The authorization servers each include afirst transmission unit configured to transmit, upon receiving theauthorization request, an authentication request for authenticating theuser to the first authorization server that is specified by the firstspecifying unit, the user information about the user who authorizes theaccess being located in the first authorization server. The firstauthorization server includes a second transmission unit configured toauthenticate the user upon transmission of the authentication request bythe first transmission unit, and to transmit, to the client, anauthorization response as a response to the authorization requesttogether with information indicating, as a transmission destination, thefirst authorization server in which the user information about theauthenticated user is located. The client includes a third transmissionunit configured to transmit a token request for requesting anauthorization token for accessing the resource server to the firstauthorization server that is specified by the second specifying unitbased on the authorization response transmitted by the secondtransmission unit, The first authorization server includes an issuanceunit configured to issue the authorization token in response to thetoken request transmitted by the third transmission unit.

Further features of the present invention will become apparent from thefollowing description of exemplary embodiments with reference to eattached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating a network configuration of aninformation processing system.

FIG. 2 is a block diagram illustrating a hardware configuration ofvarious devices.

FIG. 3 is a block diagram illustrating a software configuration ofvarious devices constituting the information processing system.

FIG. 4 is a block diagram illustrating functions included in a tokenprovider.

FIG. 5 is an authorization flowchart in the information processingsystem.

FIG. 6 is a flowchart illustrating token request processing in a client.

FIG. 7 is a flowchart illustrating token response processing in anauthorization server.

FIGS. 8A and 8B are diagrams each illustrating an example of anauthorization request (authorization assertion) claim in a JavaScriptObject Notation (JSON) Web Token (JWT) format.

FIGS. 9A and 9B are diagrams each illustrating an example of an id_tokenclaim.

FIGS. 10A and 10B are diagrams each illustrating an example of a tokenrequest (token assertion) claim.

FIG. 11 is a diagram illustrating an example of a token responseincluding user movement destination information.

FIG. 12 is a diagram illustrating an example of an authorizationconfirmation screen.

FIG. 13 is a flowchart illustrating processing performed during clientregistration.

DESCRIPTION OF THE EMBODIMENTS

User information described above is managed by an authorization serverin a specific region (hereinafter referred to as a region). In a casewhere a plurality of pieces of user information correspondingrespectively to a plurality of users is provided, these pieces of userinformation are not always collectively managed by one authorizationserver. For example, if an application is distributed to a plurality ofregions and used worldwide, user information about a user who uses theapplication is managed by an authorization server in a region in whichthe user is located. The authorization server in which the userinformation is located issues an authorization token. The authorizationtoken is issued by the authorization server corresponding to thelocation of the user information. This is because movement or sharing ofthe user information to another region is limited from a viewpoint ofpersonal information protection, security, and the like, and the user isauthenticated using the user information of which the movement orsharing is limited. When an authorization is granted by theauthenticated user, the authorization token is issued.

The authorization is granted by the user through an authorizationconfirmation screen (described below) that is displayed as a result oftransmitting an authorization request to the authorization server from aclient. Assuming that an application is used in a plurality of regions,there are a large number of options for the authorization server towhich the authorization request is transmitted. Accordingly, a tokenprovider needs to specify the authorization server to which theauthorization request is transmitted and in which the user informationis located.

As a method for specifying the authorization server, for example, amethod of designating a region by a user's operation may be employed.However, this method. requires a troublesome manual operation and causesa security issue in that selection of a region is left to the user'soperation.

The present invention is directed to appropriately selecting anauthorization server in which user information is present whilemaintaining security, and to issue an authorization token by theselected authorization server. According to the present invention, it ispossible to appropriately select an authorization server in which userinformation is present while maintaining security, and to issue anauthorization token by the selected authorization server.

Exemplary embodiments for carrying out the present invention will bedescribed below with reference to the drawings. When there is no need todistinguish between authorization servers 200 and 201 described below,the authorization servers 200 and 201 are referred to as “authorizationserver 200 (201)”. When there is no need to distinguish between resourceservers 300 and 301 described below, the resource servers 300 and 301are referred to as “resource server 300 (301)”. When the authorizationserver 201 issues an authorization token, an application programinginterface (API) released by the resource server 301 is accessed usingthe authorization token issued by the authorization server 201. The sameholds true for a relationship between the authorization server 200 andthe resource server 300.

An information processing system according to a first exemplaryembodiment of the present invention will be described with reference toFIG. 1. The information processing system is implemented by a networkconfiguration as illustrated in FIG. 1. A wide area network (WAN) 100 isconstructed by a World Wide Web (WWW) system. The WAN 100 and variousdevices 200 to 500 are connected via a local area network (LAN) 101.

The authorization server 200 (201) is a server that implements OAuth 2.0and performs processing such as reception and management of anauthentication request. FIG. 1 illustrates a configuration in which theauthorization server 200 and the resource server 300 are connected viathe LAN 101 and the authorization server 201 and the resource server 301are connected via the LAN 101. However, a configuration in which theauthorization server 200 and the resource server 300 are connected viathe WAN 100 and the authorization server 201 and the resource server 301are connected via the WAN 100 can also be used.

The authorization server 200 (201) is connected to a database server(not illustrated) via the LAN 101. Data used by the authorization server200 (201) to implement its own function may be stored in the databaseserver. The present exemplary embodiment is described assuming that theauthorization server 200 and the resource server 300 are separateservers and the authorization server 201 and the resource server 301 arealso separate servers. However, the physical configuration of variousservers is not particularly limited thereto. For example, functions ofboth types of servers may be configured on the same server, or afunction of a single authorization server or a single resource servermay be implemented by a plurality of servers.

The configuration in terms of location of the resource server 300 andthe authorization server 200 (or the resource server 301 and theauthorization server 201) is not limited to a configuration in whichboth of the servers are located in the same region or in the samesystem, The configuration in which the both servers are located is notparticularly limited as long as the resource server 300 can make aninquiry about an authorization token issued by the authorization server200. Alternatively, the resource server 300 may verify signatureinformation received together with the authorization token.

Examples of the client 400 include a printer, a multifunction peripheral(MEP), a personal computer (PC), and a smartphone. The terminal 500includes a web browser 510. Examples of the terminal 500 include a PCand a smartphone. A user can use the functions of the various devices200 to 500, such as a user authentication request to the authorizationserver 200 (201) and a login operation performed on the client 400,through the web browser 510.

The client 400 also includes a web browser 410. The user executes anauthorization operation described below by operating the web browser 410or the web browser 510. The client 400 and the terminal 500 areconnected via the LAN 101. When there is no need to distinguish betweenthe web browsers 410 and 510 to be used to execute the operation, theweb browsers 410 and 510 are hereinafter referred to as the “web browser410 (510)”.

in the present exemplary embodiment, the client 400, the terminal 500,the authorization server 200, and the resource server 300 are located ina region “jp”, and the authorization server 201 and the resource server301 are located in a region “eu”. The term region used in the presentexemplary embodiment refers to a region where there are some kind oflimitations in term of information technology, laws, and the like on themovement of the user information to the outside of the region from aviewpoint of personal information protection, security, and the like.

Referring next to FIG. 2, the hardware configuration of each of theauthorization server 200 (201), the resource server 300 (301), theclient 400, and the terminal 500 will be described. FIG. 2 is a blockdiagram illustrating a general information processing apparatus. Thehardware configuration of the general information processing apparatusor a virtual hardware configuration of an information processingapparatus provided as an Infrastructure as a Service IaaS can be appliedto the various devices 200 to 500 according to the present exemplaryembodiment. Although FIG. 2 illustrates the hardware configuration bytaking the client 400 as an example, the resource server 300 (301), theauthorization server 200 (201), and the terminal 500 also have ahardware configuration similar to that of the client 400.

A central processing unit (CPU) 2001 is a unit that reads a program froma random access memory (RAM) 2002, a read-only memory (ROM) 2003, anexternal memory 2011, or the like, executes instructions of the program,and controls the client 400. A sequence described below is implementedby executing the instructions of the program. In addition, the CPU 2001also controls each block connected to a system bus 2004.

The RAM 2002 is a work memory used by the CPU 2001 to execute theinstructions. A program such as an operating system (OS) and anapplication stored in the ROM 2003 or the external memory 2011 is loadedinto the RAM 2002. The CPU 2001 sequentially reads out the instructionsof the program, thereby executing the instructions. The ROM 2003 is astorage device on which a built-in program including an applicationprogram and an OS, and data is recorded.

A keyboard controller (KBC) 2005 is a unit that controls an input from akeyboard (KB) 2009 or a pointing device (not illustrated). A cathode raytube controller (CRTC) 2006 is a unit that controls display of a cathoderay tube (CRT) display 2010. A disk controller (DKC) 2007 is a unit thatcontrols data access to the external memory 2011. A network controller(NC) 2008 executes control processing on communication with anotherdevice connected via the WAN 100 or the LAN 101. A virtual informationprocessing apparatus provided as an IaaS does not include the KBC 2005and the CRTC 2006, and is configured to be operated through a keyboardor a CRT display included in a terminal connected via the NC 2008.

In the following descriptions, unless otherwise noted, the CPU 2001 isthe main piece of hardware that executes the functions of the variousdevices 200 to 500, and a program installed in the RAM 2002, the ROM2003, the external memory 2011, or the like is the main piece ofsoftware.

Referring next to FIG. 3, functions included in the authorization server200 (201), the resource server 300 (301), the client 400, and theterminal 500 will be described. The authorization server 201 includesfunctions similar to the functions of the authorization server 200, andthe resource server 300 includes functions similar to the functions ofthe resource server 301. Accordingly, in FIG. 3, the client 400, theauthorization server 200, and the resource server 300 are described byway of example.

The authorization server 200 includes an authorization server unit 210and a HyperText Transfer Protocol (HTTP) server unit 220. The HTTPserver unit 220 is a function that is connected to each of the client400 and the terminal 500 via the WAN 100, and performs HTTPcommunication with the web browser 410 (510) and an application 420described below. The HTTP server unit 220 can communicate by usingSecure Sockets Layer (SSL)/Transport Layer Security (TLS) and includes acertificate store (not illustrated).

The authorization server unit 210 is a function that receives a requestfrom the web browser 410 (510) via the HTTP server unit 220 and sends aresult of the received request as a response. More specifically, theHTTP server unit 220 receives a request for user authentication from theweb browser 410 (510) and generates an authentication token associatedwith user information of a user who is successfully authenticated. Thegenerated authentication token is sent to the web browser 410 (510). Theauthentication token is a token indicating that the user has logged into the authorization server 200, or a token for verifying whether theuser is authenticated in the authorization server 200. By using theauthentication token, the authorization server 200 can identify theuser. The authorization server unit 210 can also be configured to hold aprivate key for providing the authorization token with signatureinformation. In this case, the private key is used to provide theauthorization token with the signature information, and theauthorization token with the signature information is issued to theclient 400.

The resource server 300 includes a resource server unit 310. Theresource server unit 310 is a function that releases the API forproviding a web service. Similar to the authorization server 200, theresource server 300 may be configured to include an HTTP server unit andto transmit and receive information o and from an external apparatus viathe HTTP server unit.

The client 400 includes the web browser 410, the application 420, anauthentication unit 430, and the token provider 440. The web browser 410is a function that is implemented by a user agent for using the WWW. Theweb browser 410 communicates with the authorization server 200 and thetoken provider 440 by a user's operation. The web browser 510 includedin the terminal 500 is a function similar to the web browser 410. Theapplication 420 is a function that acquires the authorization token fromthe authorization server 200 via the token provider 440. The application420 can utilize the API, which is released by the resource server 300,by using the acquired authorization token.

The token provider 440 receives an authorization token request from theapplication 420 and communicates with the authorization server 200 toacquire the authorization token. The user communicates with theauthorization server 200 and the token provider 440 by using the webbrowser 410 (510), thereby performing the authorization operation.

The term “authorization token request” used herein refers to a requesttransmitted to the token provider 440 by the application 420 to acquirethe authorization token. The term “token request” used herein refers toa request transmitted to the authorization server 200 (201) by the tokenprovider 440 to acquire the authorization token. It should be noted thatthese requests have different names because transmission destinationsand transmission sources of the requests are different even though bothof the requests are made to acquire the same authorization token.

The token provider 440 includes, as vendor default credentials, a clientcertificate defined in an X.509 format to certify the token provider 440itself, and a private key for the client certificate. By the tokenprovider 440 using the client certificate and the private key thereforto establish communication with the authorization server 200, theauthorization server 200 can authenticate the token provider 440.

The authentication unit 430 is a function that authenticates the user.The user inputs a local user ID and a local user password on an inputscreen (not illustrated) of the client 400 to use a function of theclient 400. The client 400 that has received input information comparesthe input information with information (the local user ID and the localuser password) that is preliminarily registered in the authenticationunit 430 to perform authentication processing of the user and togenerate a login context. The authentication processing is not limitedto this configuration. For example, authentication using an integratedcircuit (IC) card or biometric authentication using a fingerprint or thelike may also be used.

The term “login context” used herein refers to information foridentifying a local user in the client 400. For example, the logincontext includes a local user ID. The login context is generated in theOS (not illustrated) of the client 400 when the local user logs in tothe client 400, and the login context is deleted when the local userlogs off the client 400. When the login context is generated by a loginoperation by the local user, a web page to which the logged-in localuser has access authority is released on the web browser 410. The logincontext is deleted by a log-off operation by the local user so thatsecurity is ensured while preventing the web page to which the localuser has access authority from being released to another user. The logincontext generated by the authentication unit 430 is shared among theapplication 420, the authentication unit 430, and the token provider440.

The present exemplary embodiment describes a configuration in which theuser performs the login operation by directly operating the client 400.However, a. configuration in which the user performs the login operationby remotely operating the client 400 through the web browser 510 canalso be used. In this case, the authentication unit 430 returns a loginscreen (not illustrated) to the web browser 510. The user inputs thelocal user ID and the local user password on the login screen to havethe user information authenticated.

Functions included in the token provider 440 will be described withreference to FIG. 4. The token provider 440 includes an end pointselection unit 610, a token acquisition unit 620, a token managementunit 630, a token distribution unit 640, a client registration unit 650,a key management unit 660, an assertion JavaScript Object Notation(JSON) Web Token (JWT) generation unit 670, and an id_token verificationunit 680.

The end point selection unit 610 is a function that transmits anauthorization request to an authorization end point in an authorizationflow described below. In this case, the end point selection unit 610selects an authorization end point Uniform Resource Identifier (URI)common to all regions (hereinafter, referred to as an all regions commonURI), Table 1 illustrates an example of the all regions common URI.

TABLE 1 All Regions Common URI No. Authorization End Point URI 1https://example.com/oauth2/authorize

Table 1 includes columns for “No.” lumber) and. “Authorization End PointURI”, and the all regions common URI is registered in the “AuthorizationEnd Point URI”. The registration of the all regions common URI in Table1 may be executed using an external application or the like. Theconfiguration for registering the all regions common URI in Table 1 isnot particularly limited.

The token acquisition unit 620 is a function that transmits a tokenrequest to a token end point in the authorization flow described below.The token end point is determined by the token acquisition unit 620based on id_token described below.

The token management unit 630 is a function that manages, for each localuser ID, the authorization token acquired by the token acquisition unit620. Table 2 illustrates an example of a token database managed by thetoken management unit 630.

TABLE 2 Token Database No. Local User ID Region Authorization Token 1Local_user1 jp 77qfvfm6wkl8vjvckkli2sat35yb9j 2 Local_user2 euwsmkhii4roya2nluhblqdmekdrgqwb 3 Local_user3 eut3geevyl8czkcb9lujmtgchmuyivzg

Table 2 includes columns for “No.”, “local user ID”, “region”, and“authorization token”, and the local user ID is set as a main key. Table2 is generated or updated by executing the authorization flow (S1.0 toS2.2) described below, and is managed by the token management unit 630.In this case, information stored. in the “region” is informationacquired from the id_token described below, and indicates the region ofthe authorization server from which the authorization token is acquired.

The token distribution unit 640 is a function that specifies, based onTable 2, the region information and the authorization token associatedwith the local user ID (included in the authorization token request)that is received from the application 420, and transmits theauthorization token to the application 420.

If the local user ID received from the application 420 is not present inTable 2, it is determined that the authorization flow illustrated inFIG. 5 is not executed. Further, the end point selection unit 610executes the authorization flow illustrated in FIG. 5, and stores theacquired authorization token, local user ID, and region informationacquired from the id_token described below in the token management unit630 (Table 2).

The client registration unit 650 is a function that performs clientregistration for registering the client 400 in the authorization server200 (201). The key management unit 660 holds an assertion private key(encryption key for assertion JWT signature) that is acquired during theclient registration. This key is used to make a signature for anauthorization assertion and a token assertion described below.

The key management unit 660 preliminarily holds an id_token public key(decryption key for verifying the signature of id_token) correspondingto an id_token private key (encryption key for providing the id_tokenwith a signature) held in the authorization server 200 (201), and has afunction for holding and acquiring the keys.

The assertion JWT generation unit 670 is a function that generates theauthorization assertion and the token assertion described below by usingthe assertion private key held in the key management unit 660. Theid_token verification unit 680 is a function that verifies the id_tokendescribed below by using the id_token public key held in the keymanagement unit 660. The token provider 440 includes the functionsdescribed above.

A client registration flow and an authorization flow will be describedwith reference to FIGS. 5 and 13. Detailed descriptions of theprocessing described above will be omitted.

Referring first to FIG. 13, processing to be performed during the clientregistration will be described. As a preliminary operation for executingthe authorization flow according to the present exemplary embodimentbased on the Authorization Code Grant in OAuth 2.0, in step S0.0, aregistration request for registering the client 400 is sent to theauthorization server 200. More specifically, the registration requestfor registering the client 400 is transmitted to a registration endpoint (in FIGS. 5 and 13, end points are indicated by “EP”) in theauthorization server 200, and the registration request processing isstarted when the client 400 is activated or when the client 400 is notregistered at the time of starting the authorization flow in step S1.1described below. Examples of a method for transmitting a clientregistration request include a method in which the client registrationunit 650 of the token provider 440 actively communicates with theauthorization server 200, and a method in which the user accesses theauthorization server 200 through the web browser 510 to register theclient 400.

The client registration request in step S0.0 includes a client name, adescription, an icon image, and a redirect Uniform Resource Identifier(URI) as an essential parameter, which are to be displayed on theauthorization confirmation screen described below. The redirect URI isan address that designates a transmission destination to which theclient 400 transmits an authorization response described below. in stepS0.1, the authorization server 200 that has received the registrationrequest for registering the client 400 generates a client ID foridentifying the client 400 and a pair of keys (an assertion public keyand an assertion private key) for authenticating the client 400, andtransmits the assertion private key to the client 400 as a response tothe registration request for registering the client 400. As a method fortransmitting the assertion private key, the assertion private key may beencrypted and transmitted using a key-exchange protocol.

The token provider 440 stores the assertion private key in the keymanagement unit 660. The authorization server 200 holds, in anassociated manner, the client ID, the assertion public key, variouspieces of information acquired in step S0.0, and the redirect URI. Thetoken provider 440 holds the client ID and the assertion private keyreceived in step S0.1 in the key management unit 660.

The client registration illustrated in FIG. 13 is executed on theauthorization server 200 that is present in the region in which thetoken provider 440 (client 400) is present. The information (the clientID, the assertion public key, etc.) about the client 400 that isgenerated and stored during the client registration is shared not onlyby the authorization server 200, but also by another authorizationserver (e.g., the authorization server 201). As a result, even when thetransmission destination of the authentication request (S1.5 describedbelow) is different from user to user, information exchangeof tokens,such as the issuance of id_token described below or the issuance of theauthorization token, can be executed using the client ID and theassertion public key that are shared among the authorization servers.

The client registration processing performed as a preliminary operationfor executing the authorization flow has been described above.

The authorization flow performed after the client registrationprocessing will be described with reference to FIG. 5.

In step S1.0, the user logs in to the client 400. The authenticationunit 430 of the client 400 generates and holds the login context, whichis information for specifying the logged-in user. By using the generatedlogin context, it is possible to acquire the information (e.g., localuser ID) for specifying the logged-in user from the login context.

In step S1.1, when the user accesses an authorization start URI throughthe web browser 510, the user starts the authorization flow based onOAuth 2.0 according to the present exemplary embodiment. In step S1.2,when the authorization start URI for starting the authorization flow isaccessed, the client 400 transmits the authorization request to theauthorization end point. The authorization end point is accessed via anall regions common URI.

<Authorization End Point>

A method for specifying the authorization end point will now bedescribed. To select an appropriate authorization server and acquire anauthorization token, the token provider 440 first transmits anauthorization request to the all regions common URI. A Domain NameSystem (DNS) server that is accessed as a result of transmitting theauthorization request manages data (DNS record) that associates anauthorization end point URI with an Internet Protocol (IP) address. Anaccess to the authorization server through the web browser is made viathe DNS server, and the authorization end point URI common to the allregions is converted (name resolution) into an IP address based on theDNS record. In this case, a Geo Routing georouting function (GeoRoutingfunction in the case of Amazon Web Services (AWS)) references ageographic database based on the IP address of the authorization requestsource (client 400), the IP address is converted into an appropriateauthorization end point URI, and the authorization end point URI istransmitted to the authorization request transmission source.

In the present exemplary embodiment, the client 400 and theauthorization server 200 are present in the same region “jp”.Accordingly, in the case of accessing the all regions common URI throughthe web browser MO, the authorization end point URI of the authorizationserver 200 present in the same region “jp” is returned to the tokenprovider 440 by the georouting function. The token provider 440transmits the authorization request to the authorization end point URI.Step S1.2 illustrated in FIG. 5 indicates a state where theauthorization request is transmitted to the authorization end point URIspecified by the georouting function.

<Authorization Request>

The authorization request transmitted by the token provider 440 will bedescribed. When the token provider 440 transmits the authorizationrequest, a request for acquiring security information (id_tokendescribed below) is also transmitted.

The authorization request is represented in a JWT format with asignature, including response_type, client_id, redirect_uri, and a stateparameter. For convenience of description, the authorization request inthe JWT format is hereinafter referred to as an “authorizationassertion”. The authorization assertion includes a. header and payloaddescribed below.

The authorization assertion is provided with a signature using theassertion private key acquired in the client registration response instep S0.1 in response to the authorization request, and ES256 (ECDSAusing P-256 curve and SHA-256 hash) defined in RFC7518 JSON WebAlgorithms (JWA) is used as a signature algorithm. FIG. 8A illustratesan example of the header of the authorization assertion.

In FIG. 8A, “typ” represents a type of JWT to which “Assertion” is setas a value indicating the type is the assertion JWT, “alg” represents asignature algorithm to which a value “ES256” is set, and “kid”represents an ID for the assertion public key and the assertion privatekey that is used to verify the signature of JWT. Examples of the valueset as “kid” include a Universally Unique Identifier (UUID) and athumbprint of a public key based on JSON Web Key (JWK) Thumbprint (RFC7638) specifications.

FIG. 8B illustrates an example of a payload claim of the authorizationassertion. In FIG. 8B, “response type” represents a response type inOAuth 2.0. To acquire id_token in the authorization response describedbelow, a value “id_token” is set to the “response type”.

An identifier for identifying an issuer of JWT is represented by “iss”.In the case of authorization assertion, the UUID indicating a client IDis set as a value. A user identifier is represented by “sub”, and theUUID indicating the client ID is set, similar to the “iss”, The “iss”and “sub” are included in the authorization request in the JWT format byencoding character strings represented by using a URI-safe Base64 formatfor each of the “iss” and “sub”. An expiration date of the authorizationassertion is represented by “exp”, and a date and time of issuance ofthe authorization assertion s represented by “iat”. Both of the “exp”and “i at” are represented by elapsed seconds from the Unix Epoch (Jan.1, 1970 (world standard time)).

The payload claim illustrated in FIG. 8B also includes “state” and“redirect_uri” representing the redirect URI in OAuth 2.0. The “state”represents information for uniquely associating the authorizationrequest with the authorization response, and is used to prevent across-site request forgery (CSRF) attack or a token substitution attack.Thus, a unique value that cannot be estimated needs to be set as the“state”. The client 400 that has received the authorization responsedescribed below verifies whether the value of the state matches thevalue of the state transmitted in the authorization request in stepS1.2. To identify the local user who has executed the authorizationrequest, the “state” issued by the client 400 is managed by the client400 in such a manner that the “state” is associated with each of theredirect URI and the login context.

The token provider 440 creates the authorization assertion asillustrated in FIGS. 8A and 8B based on the JWT specifications. Theauthorization assertion is provided with a signature (not illustrated)in the JWT format by using the assertion private key described above.The authorization request has been described above.

Referring back to FIG. 5, in step S1,3, the authorization server 200that has received the authorization request in step S1.2 returns a loginscreen common to the all regions to the web browser 510. The loginscreen includes the authorization assertion in a hidden field. In stepS1.4, the user inputs the user II) and the password through the webbrowser 510, and sends the authentication request to the authorizationserver 200. At that time, the authorization assertion, which ispreviously received as the hidden field in the login screen, and theauthentication request are simultaneously posted. In this case, the userID transmitted to the authorization server 200 in step S1.4 is a useridentifier for logging in to the authorization server and is differentfrom the local user ID used in step S1.0.

in step S1.5, the authorization server 200 determines a user IDaffiliation region (region for the authorization server to manage userinformation about the user specified by the user ID), and redirects thelogin screen to the authorization server in an appropriate region. Table3 illustrates an example of a user affiliation region table shared amongthe authorization servers in different regions.

TABLE 3 User Affiliation Region Table Affiliation No. User ID (HashValue) Region 1b927736961c523464a5559982a527eccd18277cbeeec092ea67959990241bcc3 jp 28afe0cae0d1a4fbb380348ff1999aa1d40ecf829a730b82bdcb6a628796b51b2 eu 325dac1eaecc81673cb64157be38babb6a13b53b020e2d88dfdca70054c84cf03 jp

The user ID (hash value) is a hash value calculated by a Secure HashAlgorithm (SHA)-256 algorithm for each user ID character string. Theaffiliation region is a region to which the user specified by the userID belongs. Table 3 illustrates that the affiliation region of “user1@110AA” (hash value:b927736961c523464a5559982a527eccd18277cbeeec092ea67959990241bcc3) is“jb”, the affiliation region of “user2@110Ab” (hash value:8afe0cae0d1a4thb380348ff1999aa1d40ecf829a730b82bdcb6a628796b51b2) is“eu”, and the affiliation region of “user3@120AA” (hash value:25dac1eaecc81673cb64157be38babb6a13b53b020e2d88dfdca70054c84cf03) is“jp”.

The user affiliation region table (Table 3) is updated during the userregistration, and latest data is periodically shared among theauthorization servers in the all regions. Since the user D isrepresented by a hash value, it is generally impossible to restore theuser ID from this value. Accordingly, sharing the user affiliationregion table (Table 3) among the authorization servers in the allregions does not mean that the user information is shared.

Redirect of the login screen in step S1,5 will be described. A case isdescribed where the user ID “user2@110Ab” and the password “password”are input on the all regions common login screen in step S1.3. Theauthorization server 200 calculates a hash value for the input user ID.From the calculated hash value with reference to Table 3, theaffiliation region “eu” of the user is specified. The user ID, thepassword, and the authorization assertion posted in the authenticationrequest are returned to a cookie in the web browser 510, and areredirected, as the authentication request, to a login URI for theauthorization server 201, which is the authorization server belonging tothe region “eu”.

The present exemplary embodiment illustrates a configuration in whichthe login URI for the authorization server 201 is specified from theaffiliation region stored in Table 3. More specifically, the type of thelogin URI for each of the authorization servers in different regions isdetermined in advance, and the “affiliation region” illustrated in Table3 is applied to the type, thereby specifying the login URI for each ofthe authorization servers. However, the configuration of the presentexemplary embodiment is not limited to this configuration (Table 3).Alternatively, a configuration may be used where the login URI for eachof the authorization servers and the hash value for each user ID aremanaged in such a manner that the login URI is associated with the hashvalue.

The authorization server 201 verifies whether the associatinginformation that associates the user ID and the password, which areredirected in step S1.5, matches the associating information registeredin advance. If the pieces of associating information match, theauthentication token is issued. The issued authentication token isreturned to the cookie in the web browser 510. Redirect of the loginscreen has been described above.

Referring back to FIG. 5, in step S1.6, the authorization server 201returns, to the web browser 510, the authorization confirmation screenused for confirming whether the user agrees to the authorization of theclient 400. FIG. 12 illustrates an example of the authorizationconfirmation screen. An authorization confirmation screen 1200 includesa client name 1201 of the client 400 to be authorized, a description1202 about the client 400, and an icon image 1203, as contents withwhich the user is asked to agree. The authorization confirmation screen1200 also includes a “PERMIT” button 1204 used by the user to authorizethe client 400, and a “DENY” button 1205 used by the user to deny theauthorization. Processing to be performed when the “DENY” button 1205 ispressed or processing to be performed when the “PERMIT” button 1204 ispressed (S1.7) will be described below.

The authorization confirmation screen includes, as a hidden field, theauthorization assertion included in the redirected authenticationrequest. However, after the signature of the authorization assertionincluded in the authentication request is verified, if a combination ofthe client ID and the redirect URI included in the authorizationassertion does not match a combination of the client ID and the redirectURI shared with the authorization server 201 and an authorization serverin another region, an error screen is returned to the web browser 510instead of the authorization confirmation screen. Thus, an unauthorizedredirect to a login URI can be prevented. Similarly, when the “DENY”button 1205 of the authorization confirmation screen 1200 is pressed,the error screen is transmitted to the web browser 510.

If the user who has logged in to the authorization server 201 hascompleted the authorization operation using the same client ID, theprocessing of steps S1.6 and S1.7 can be omitted.

After the “PERMIT” button 1204 is pressed and the authorizationoperation is executed by the user in step S1.7, in step S1.8, theauthorization server 201 posts the authorization assertion included inthe authorization operation to the authorization end point of theauthorization server 201. The authorization server 201 verifies theauthorization assertion posted to the authorization end point. Thereason for verifying the authorization assertion in this case is thatthe authorization assertion is an instruction (authorization operationin this case) received from an apparatus (web browser 510), which isexternal to the authorization server 201. Thus, there is a need toverify whether the content of the authorization assertion is notfalsified.

If the verification of the authorization assertion is successful, instep S1.9, id_token is generated, and the generated id_token istransmitted as the authorization response to the redirect URI for theclient 400. More specifically, the generated id_token is transmitted tothe client 400 from the authorization server 201 through the web browser510. In transmitting the generated id_token, the id_token is provided asa query parameter for the redirect URI and is transmitted to the webbrowser 510. As a result, the id_token is redirected to a destinationdesignated by the redirect URI. The id_token generated by theauthorization server 201 is stored in the authorization server 201 inassociation with the client ID, the user ID, and the redirect URI.

If the verification of the authorization assertion is unsuccessful instep S1.8, the authorization server 201 returns an authorization errorto the web browser 510.

<id_token>

The id_token generated by the authorization server 201 is a securitytoken including a claim about the end user authentication by theauthorization server, and is defined in OpenID Connect specifications(OpenID Foundation OpenID Connect Core 1.0). The id_token includesregion information about the region in which the authorization token isused, and is represented by a JSON Web Token with a signature (JWTRFC7518, JWT RFC7515). In general, the id_token includes a claim setabout the end user authentication (claims about the authentication), anda claim set about the other user attributes. The id_token according tothe present exemplary embodiment includes “iss”, “sub”, “aud”, “exp”,“iat”, and “nonce” in the payload claim.

The signature of the id_token is provided using the id_token privatekey, and an ES256 signature defined in the JWA is used as a signaturealgorithm. FIG. 9A illustrates an example of the header of the id_token.Descriptions of the parts described above with reference to FIGS. 8A and8B will be omitted.

The header of the id_token includes the signature algorithm “ES256” ofthe id_token represented by “alg” and “kid” representing an ID for theid_token public key and the id_token private key that is used to verifythe signature of the id_token. As “kid”, the UUID and a thumbprint of apublic key based on MK Thumbprint (RFC 7638) specifications may be used.

FIG. 9B illustrates an example of a claim about a user attribute presentin the payload of the id_token. A URI starting with “https://” that doesnot include a query and a fragment portion is set to “iss” based on thedefinition of OpenID Connect Core 1.0. In this case, since an issuer ofthe id_token is the authorization server 201,“https://eu-auth.example.com” representing the authorization server 201is set.

An issuance object of the id_token is represented by “aud”. In thiscase, a value of the client ID is set as the “aud”. The “sub” and “aud”are character strings each represented in a URI-safe Base64 format. Theid_token includes “nonce” mainly for a purpose of preventing a replayattack, and a value of the “state” parameter is set as the “nonce”. Theid_token has been described above.

Referring back to FIG. 5, the id_token private key is required forproviding the signature to the id_token, and the id_token public key isrequired for verifying the id_token. A case is described where theid_token private key is shared in advance among the authorizationservers in respective regions and the id_token public key ispreliminarily stored in the client 400.

The client 400 that has received the authorization response in step S1.9verifies the signature (not illustrated) of the id_token included in theauthorization response, and determines whether the “nonce” included inthe id_token matches the “state” managed by the client 400. If it isdetermined that the “nonce” matches the “state”, the client 400 acquiresthe URI for the authorization server 201, which is the issuer of theid_token, with reference to the “iss” in the id_token. In this case, theid_token verification unit 680 of the token provider 440 acquires theURI “https://eu-auth.example.com” for the authorization server 201 withreference to the “iss” in the id_token. A region character string isrecognized with reference to a character string “eu” before the hyphenin a host name “eu-auth” in the acquired URI for the authorizationserver 201. The recognized region character string is stored in thetoken database (Table 2).

The token database also stores the local user ID of the user who iscurrently logged in to the client 400. In step S2.0, a token request foracquiring the authorization token is transmitted to the token end pointof the authorization server 201. The token request is described in theJWT format. To distinguish the token request from the assertion JWT usedduring the authorization request, the token request in the JWT format ishereinafter referred to as “token assertion”. The token assertionincludes a header and a payload. The token assertion also includes aclient ID, a user ID acquired from a sub claim in the iktoken, and aredirect URI. FIG. 10A illustrates an example of the header of the tokenassertion.

In FIG. 10A, “typ” represents a type of MT to which “Assertion” is setas a value indicating the type is the assertion JWT. The header alsoincludes “alg” representing a signature algorithm that is set to“ES256”, and “kid” representing an ID for the assertion public key andthe assertion private key that is used to verify the signature of JWT.As “kid”, the UUID and a thumbprint value for a public key based on JWKThumbprint (RFC 7638) specifications may be used.

FIG. 10B illustrates an example of the payload claim about the tokenassertion. Descriptions of the parts described above will be omitted.

In FIG. 10B, “response type” represents a response type in OAuth 2.0 towhich “id_token” is set. The payload claim also includes “iss”representing a client ID in OAuth 2.0, “redirect_uri” representing aredirect URI in OAuth 2.0, and “sub” representing a user identifier. Inthe present exemplary embodiment, the value included in the id_tokenpreviously acquired is set as the “sub”.

The token provider 440 creates the token assertion including the headerand the payload as illustrated in FIGS. 10A and 10B based on the NTTspecifications. The token assertion includes the signature providedusing the assertion private key acquired in the client registrationresponse (details of the signature in JWT is omitted).

The authorization server 201 that has received the token request in stepS2.0 verifies the signature of the token assertion by using theassertion public key. Further, the authorization server 201 analyzes thetoken assertion received in step S2.0, and acquires the “iss”, the“sub”, the “redirect uri”, the “iat”, and the “exp”, By analyzing theacquired information, the authorization server 201 can verify whetherthe client 400 that has transmitted the authorization request in stepS1.2 matches the client 400 that has transmitted the token request instep S2.0, and whether the user information about the user who requeststhe authorization token is present in the authorization server 201.

If the verification is successful, in step S2.1, the authorizationserver 201 transmits the authorization token as the token response tothe client 400. The token management unit 630 of the token provider 440stores the acquired authorization token in the token database (Table 2).

in step S3.0, the token distribution unit 640 of the token provider 440searches for the user ID of the user who is currently logged in from thetoken database (Table 2) included in the token management unit 630, andacquires the region information and the authorization token. Theacquired region information and authorization token are transmitted tothe application 420.

In step S3.1, the application 420 accesses the API released by theresource server 301 based on the received authorization token and regioninformation. More specifically, the application 420 accesses the APIreleased by the resource server 301 by using a resource server URI (notillustrated) for each region that is preliminarily incorporated in theapplication 420 and the region information acquired from the tokenprovider 440. In the present exemplary embodiment, the resource requestin step S3.1 is transmitted. to the resource server 301 that is presentin the same region “eu” as the authorization server 201 that manages theuser information.

The authorization flow has been described above. According to thepresent exemplary embodiment, it is possible to appropriately select theauthorization server in which the user information is present withoutany manual operation by the user, and to enable the selectedauthorization server to issue the authorization token. In addition, byusing the acquired authorization token, it is possible to request theresource server in the region in which the user information is presentto send resources.

A second exemplary embodiment describes a configuration in whichacquisition of a token is continued in a case where a user moves toanother region after the authorization request (S1.2) and theauthorization response (S1.9) are normally completed and before thetoken request is transmitted (S2.0).

More specifically, a case is assumed where the user authorized in stepsS1.2 to S1.9 has moved to another region due to a business trip, movinghome, or the like. In this case, user information about the user who hasmoved needs to be moved to the authorization server in the region of themovement destination. A situation is assumed where, during the movementof the user information, the token request is transmitted to theauthorization server that has authorized the user before the user movesto another region.

Referring first to FIG. 6, processing to be performed when the userinformation about the authorized user is moved from the authorizationserver 201 during a period from the authorization response (S1.9) to thetoken request (S2.0). The processing illustrated in FIG. 6 is tokenrequest processing to be executed mainly by the token provider 440(client 400).

In step S6.0, the token provider 440 transmits the authorization requestto the authorization server 200. This processing is similar to theprocessing of step S1.2 in the first exemplary embodiment. In step S6.1,the token provider 440 receives the authorization response. Thisprocessing is similar to step S1.9 in the first exemplary embodiment. Inthis case, the token provider 440 verifies id_token included in theauthorization response. After the verification, in step S6.2, the tokenprovider 440 transmits the token request (token assertion) in the JWTformat to the token end point of the authorization server 201, and instep S6.3, the token provider 440 receives the token response to thetoken request. in step S6.4, the token provider 440 analyzes the tokenresponse and determines whether the token response includes theauthorization token. If it is determined that the authorization token isincluded (YES in step S6.4), the processing proceeds to step S3.0,similar to the first exemplary embodiment. If it is determined that theauthorization token is not included (NO in step S6.4), the processingproceeds to step S6.5. in step S6.5, the token provider 440 determineswhether the token response includes user movement destinationinformation.

FIG. 11 illustrates an example of the token response including the usermovement destination information. In FIG. 11, “destination_uri”represents a movement destination token end point that is determined bythe authorization server 201 as a movement destination of userinformation based on the user movement destination information describedbelow.

If it is determined that the token response includes the user movementdestination information in step S6.5 (YES in step S6.5), the processingreturns to step S6.2, and the token request is transmitted again to themovement destination token end point specified by the user movementdestination information. The processing orf steps S6.2 to S6.5 isrepeatedly executed as long as the “destination_uri” is included in thetoken response. In this case, however, a configuration may also be usedwhere an error occurs in the token provider 440 when the number of timesof execution exceeds a certain value or when a. certain period of timeelapses, whereby the processing is terminated.

In step S6.5, if it is determined that the user movement destinationinformation is not present in the token response (NC) in step S6.5), theprocessing returns to step S6.0, and the token provider 440 transmitsthe authorization request to the authorization server 200. Theprocessing returning to step S6.0 from step S6.5 is repeatedly executeduntil the user movement destination information is included in the tokenresponse. However, similar to the processing returning to step S6.2, aconfiguration may also be used where an rapper limit is set for thenumber of times of execution or processing time, and an error occurs inthe token provider 440 when the upper limit is exceeded, whereby theprocessing is terminated. The processing illustrated in FIG. 6 has beendescribed above.

Referring to FIG. 7, processing in which the authorization server 201that has received the token request from the token provider 440transmits the token response will be described. Similar to step S2.0, instep S7.1, the authorization server 201 receives the token assertion atthe token end point. In step S7.2, the authorization server 201 verifiesthe token assertion by using the assertion public key, and acquires theuser identifier from “sub”. At that time, in step S7.3, theauthorization server 201 determines whether the acquired user identifieris present in the authorization server 201. If it is determined that theuser identifier is present in the authorization server 201 (YES in stepS7.3), the processing proceeds to step S7.4. In step S7.4, theauthorization token is transmitted as the token response to the client400, similar to step S2.1 of the first exemplary embodiment. If it isdetermined that the user identifier is not present in the authorizationserver 201 (NO in step S7.3), the processing proceeds to step S7.5. Instep S7.5, it is determined whether the user identifier is present in auser information destination table. Table 4 illustrates an example ofthe user information movement destination table to be referenced in thedetermination.

TABLE 4 User Information Movement Destination Table No. User IdentifierMovement Destination Token End Point 1 dXNlcjJAMTEwQUIhttps://us.example.com/oauth2/token

The user information movement destination table includes columns for theuser identifier and the movement destination token end point. Themovement destination token end point represents a token end point URIfor the authorization server of the movement destination of userinformation when the user information is moved to the authorizationserver in another region.

More specifically, in step S7.5, the authorization server 201 determineswhether the user identifier “dXN1cjJAMTEwQUI” included in the “sub” ofthe token assertion is present. If it is determined that the useridentifier is present (YES in step S7.5), the processing proceeds tostep S7.6. in step S7.6, the authorization server 201 acquires thecorresponding movement destination token end point, and transmits thetoken response in which the movement destination token end point URI isdescribed as the “destination_uri” to the token provider 440, The“destination_uri” represents the “user movement destination information”described in the processing illustrated in FIG. 6.

If it is determined that the user identifier is not present in step S7.5(NO in step S7.5), the authorization server 201 transmits anerrorresponse to the token provider 440 and terminates the processing.

According to the present exemplary embodiment, it is possible tocontinue the processing until the authorization token is acquiredwithout authorizing the user again even in a case where the tokenrequest is executed when the user information about the authorized useris transmitted to another authorization server.

The exemplary embodiments above describe a configuration in which thegeorouting function is used to transmit the authorization request to theauthorization server 200 that is geographically close to the tokenprovider 440 (client 400). This configuration is employed in view of anaccess time or the like. However, the method for determining thetransmission destination of the authorization request is notparticularly limited thereto as long as the transmission destination isan authorization server that shares the iliation region table (Table 3).

Other Embodiments

Embodiment(s) of the present invention can also be realized by acomputer of a system or apparatus that reads out and executes computerexecutable instructions (e.g., one or more programs) recorded on astorage medium (which may also be referred to more fully as a‘non-transitory computer-readable storage medium’) to perform thefunctions of one or more of the above-described embodiment(s) and/orthat includes one or more circuits (e.g., application specificintegrated circuit (ASIC)) for performing the functions of one or moreof the above-described embodiment(s), and by a method performed by thecomputer of the system or apparatus by, for example, reading out andexecuting the computer executable instructions from the storage mediumto perform the functions of one or more of the above-describedembodiment(s) and/or controlling the one or more circuits to perform thefunctions of one or more of the above-described embodiment(s). Thecomputer may comprise one or more processors (e.g., central processingunit (CPU), micro processing unit (MPU)) and may include a network ofseparate computers or separate processors to read out and execute thecomputer executable instructions. The computer executable instructionsmay be provided to the computer, for example, from a network or thestorage medium. The storage medium may include, for example, one or moreof a hard disk, a random-access memory (RAM), a read only memory (ROM),a storage of distributed computing systems, an optical disk (such as acompact disc (CD), digital versatile disc (DVD), or Blu-ray Disc (BD)™),a flash memory device, a memory card, and the like.

While the present invention has been described with reference toexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all such modifications and equivalent structures andfunctions.

This application claims the benefit of Japanese Patent Application No.2018-022405, filed Feb. 9, 2018, which is hereby incorporated byreference herein in its entirety.

What is claimed is:
 1. An information processing system comprising: aclient configured to transmit an authorization request used by a user toauthorize access by the client to a resource server; and two or moreauthorization servers present in different regions, wherein theauthorization servers each include a first specifying unit configured tospecify a first authorization server in which user information about theuser who authorizes the access is located, wherein the client includes asecond specifying unit configured to specify the authorization serverspresent in the regions based on region information about the regions,wherein the authorization servers each include a first transmission unitconfigured to transmit, upon receiving the authorization request, anauthentication request for authenticating he user to the firstauthorization server that is specified by the first specifying unit, theuser information about the user who authorizes the access being locatedin the first authorization server, wherein the first authorizationserver includes a second transmission unit configured to authenticatethe user upon transmission of the authentication request by the firsttransmission unit, and to transmit, to the client, an authorizationresponse as a response to the authorization request together withinformation indicating, as a transmission destination, the firstauthorization server in which the user information about theauthenticated user is located, wherein the client includes a thirdtransmission unit configured to transmit a token request for requestingan authorization token for accessing the resource server to the firstauthorization server that is specified by the second specifying unitbased on the authorization response transmitted by the secondtransmission unit, and wherein the first authorization server includesan issuance unit configured to issue the authorization token in responseto the token request transmitted by the third transmission unit.
 2. Theinformation processing system according to claim 1, wherein the clientacquires the authorization token issued by the issuance unit, and usesthe acquired authorization token to access the resource server.
 3. Theinformation processing system according to claim 1, wherein theauthorization request transmitted from the client to the authorizationservers is transmitted from the client to a common Uniform ResourceIdentifier (URI) through a web browser, and is transmitted to any one ofthe two or more authorization servers present in the different regions.4. The information processing system according to claim 3, wherein theauthorization request transmitted to the common URI is transmitted to anauthorization server located geographically close to the client that hastransmitted the authorization request.
 5. The information processingsystem according to claim 1, wherein the first specifying unit managesfirst information in which a. hash value of a user identifier foridentifying the user and region information about the firstauthorization server in which the user information about the user ispresent are associated with each other, and wherein the first specifyingunit calculates a hash value of a user identifier included in theauthentication request, and specifies the region information about thefirst authorization server based on the calculated hash value and thefirst information.
 6. The information processing system according toclaim 1, wherein the authorization response includes informationindicating the first authorization server as a destination, andsignature information about the information indicating the firstauthorization server as the destination.
 7. The information processingsystem according to claim 6, wherein the first authorization serverfurther includes a first management unit configured to manage anencryption key for providing the authorization response with thesignature information, and wherein the client further includes a secondmanagement unit configured to manage a decryption key for verifying thesignature information.
 8. The information processing system according toclaim 1, wherein the client further includes a third management unitconfigured to manage an encryption key for providing the authorizationrequest with signature information, wherein the first authorizationserver further includes a fourth management unit configured to manage adecryption key for verifying the signature information provided to theauthorization request, wherein the encryption key managed by the thirdmanagement unit provides the token request for acquiring theauthorization token with signature information, and wherein thedecryption key managed by the fourth management unit verifies thesignature information provided to the token request.
 9. The informationprocessing system according to claim 8, wherein the decryption keymanaged by the fourth management unit is shared among the two or moreauthorization servers present in the different regions.
 10. Theinformation processing system according to claim 1, wherein theauthorization servers each further include a third specifying unitconfigured to specify an authorization server of a movement destinationto which the user information is moved, wherein the client furtherincludes: a first verification unit configured to verify whether aresponse to the token request for acquiring the authorization tokenincludes the authorization token; and a second verification unitconfigured to verify whether the response to the token request foracquiring the authorization token includes information about themovement destination of the user information specified by the thirdspecifying unit, and wherein in a case where the first verification unitdetermines that the response to the token request does not include theauthorization token, the second verification unit verifies whether theresponse to the token request includes the information about themovement destination.
 11. The information processing system according toclaim 10, wherein in a case where the second verification unit verifiesthat the response to the token request includes the information aboutthe movement destination, the token request for requesting theauthorization token is transmitted to the movement destination.
 12. Theinformation processing system according to claim 10, wherein the thirdspecifying unit specifies the movement destination by using a useridentifier included in the token request received from the client.
 13. Acontrol method for an information processing system including: a clientconfigured to transmit an authorization request used by a user toauthorize access by the client to a resource server; and two or moreauthorization servers present in different regions, the control methodcomprising: specifying, by the authorization servers, a firstauthorization server in which user information about the user whoauthorizes the access is located; specifying, by the client, theauthorization servers present in the regions based on region informationabout the regions; transmitting, by the authorization servers, uponreceiving the authorization request, an authentication request forauthenticating the user to the specified first authorization server, theuser information about the user who authorizes the access being locatedin the first authorization server; authenticating the user, by the firstauthorization server, upon transmission of the authentication request bythe authorization servers, and transmitting, by the first authorizationserver, to the client, an authorization response as a response to theauthorization request together with information indicating, as atransmission destination for transmitting a token request, the firstauthorization server in which the user information about theauthenticated user is located; transmitting, by the client, a tokenrequest for requesting an authorization token for accessing the resourceserver to the first authorization server that is specified by the clientbased on the authorization response received from the firstauthorization server; and issuing, by the first authorization server,the authorization token in response to the token request received fromthe client.